Premier League leaders Arsenal dropped points for only the second time this season as Stuart Armstrong's second-half equaliser earned Southampton a hard-earned point at St Mary's.
Armstrong finished off a flowing team move involving Adam Armstrong and Mohamed Elyounoussi to stretch Saints' unbeaten league run to three matches.
Granit Xhaka had given the Gunners an early lead with his second goal in as many games, firing into the roof of the net from Ben White's low delivery.
The effervescent Gabriel Martinelli had a shot deflected wide and Gabriel Jesus was denied by Southampton goalkeeper Gavin Bazunu as the visitors threatened to double their advantage before the interval.